<div class="lbox1">
    <?php $class = empty($_GET['class'])?'my':$_GET['class']; ?>
    <a href="my.php?class=my" <?php if($class == 'my'){echo 'class="on"';}?>>我的信息</a>
    <a href="mypassword.php?class=mypassword"  <?php if($class == 'mypassword'){echo 'class="on"';}?>   >修改密码</a>

    <a href="myorder.php?class=myorder" <?php if($class == 'myorder'){echo 'class="on"';}?> >订单管理</a>
</div>